@Chris I checked out Dr. Esselstyn talk. Thanks!
I think part of the problem in this discussion is being specific about the questions we are trying to answer so let me try and do that here. I will answer based on my knowledge and opinions (to be changed as I learn more).
Q. Is it possible to lead a very healthy life with a vegetarian/vegan diet?
A. Yes, absolutely. I think anyone can get all nutrients from a purely plant based diet. In fact, I grew up on a North Indian largely vegetarian diet and if someone said that you can only have one meal combination for the rest of your life, I would choose yellow dal (yellow lentils), Okra and whole wheat rotis (side note: the only Indian restaurant that I know of that sells home cooked vegetarian North India food is Chaat House at Wolfe and El Camino in Sunnyvale. Check it out. Order the "thaali" - one with dal. You are welcome!).
Q. Can a vegetarian diet be unhealthy?
A. Yes, absolutely. Take the above meal I mentioned and use too much oil to cook the Okra/dal or add butter/ghee to the rotis; add lots of sugar to tea/coffee; eat a lot of dessert; and you will be unhealthy. Add to it lack of exercise, smoking etc. and no vegetarian diet will save you.
Q. Can you both bulk up and lose weight on a vegetarian diet?
A. It is possible but harder than with a diet that has meat. To achieve the above you need both protein and lower your calories. Meat (especially Chicken) has the highest protein per calorie. To bulk up you need protein. If you rely on plant based sources for protein, you will consume a lot more calories too and will therefore need to exercise even more to create the calorie defecit. Plus, meat fills you up more so staying a little hungry during a calorie defecit is easier with meat.
Q. Can you be an elite athlete on a vegetarian diet.
A. Yes, absolutely. And the movie provides plenty of examples. Boils down to nutrient and calorie intake and calories burned.
Q. Is a vegetarian diet the panacea?
A. NO! and I think this is where the movie and even Dr. Esselstyn's talk fall short - they try and suggest it as the panacea. If I added some meat to the vegetarian diet I suggested above, I would still be very healthy. There are many claims in even Dr. Esselstyn's talk that don't go into the full picture. Let me address them through a few questions.
Q. Would going from a cheese/meat/refined bread diet to a vegetarian diet improve your health?
A. Yes, absolutely. Dr. Esselstyn talked about the "living dead" and how changes in diet helped them. Makes perfect sense to me. But I don't see how you extrapolate from there that being vegetarian is the ONLY answer. He also did not talk about what the average diet looked like prior to the switch. He also talked about migration and how that had an impact. But moving from, say, Japan/India to US also brings with it so many more changes including (and I say this from experience having grown up in India) the role of women (moms) and cooking. The bucolic perfect vegetarian food (and all else that comes with it) is obtained by largely women/moms not joining the workforce. For immigrants, that family structure is broken and in general it is better that a larger number of women are more free to make those choices today and join the workforce. With extra pressures on time, I have seen how I have made poorer choices around food for easier cooking but I have still chosen to live in the US because there are many other benefits that outweigh the costs and now, with all the information around nutrition, we (as in men and women together) are trying to minimze those cost.
Q. Can a good diet exist without vegetables (and fruit)?
A. Absolutely not. Vegetables (and fruits) are key to health. I don't think you can deconstruct food into nutrients, fiber, etc and just take supplements and have the same health outcomes as a healthy well balanced diet. Our knowledge of the underlying components has improved a lot but I don't think we still understand the complexity of how all this comes together and how our body reacts to Okra/Eggplant/Apple/Peach. There is complexity through evolution in the vegetables and fruit and complexity in how our bodies react to them. So consuming them in their alomost original form is much better for health. My body is particularly sensitive to fiber and I feel much better getting it in natural forms than supplements.
Q. How does all this relate to specific health/wellness goals a person might have?
A1. If you are looking to simply maintain weight then a pure vegetarian diet can do just fine. But so can a balanced diet that has meat.
A2. If you are looking to lose weight (calorie defecit) and bulk up (protein), a diet with both meat and vegetables is ideal. With possibly some supplements, especially fiber.
A3. If your arteries are blocked, moving to a vegetarian diet, low/non-existent sugar/simple carbs, light exercicse will more than likely improve your condition. It might be a good idea to stay away from meat for sometime to get a break from all fats.
Q. What are some best practices (note: this is simply how I think about it)?
A. Sugar and simple carbs should be redcued. This is the one evil food. Though, in small quantities this too is fine. A tsp of sugar in your coffee once a day is not going to do any harm. But, 2 tsp / 5 times a day ... don't do that. Complex carbs are much better than simple carbs. Chicken has highest protein per calorie, and lowest in fat. Each day should be a good mix of protein, carbs (I don't buy carbs is bad dogma) and fat. Each of these macro nutrients can be quantified. For example a diet for an adult (weight / geneder play a role) with 100-125g protein, 125-150g carbs and 40-50g fat is a healthy diet. Some of these macros must come from vegetables and fruit. In short, eat everything, in moderation and exercise (and it is all measurable: measure all macros and calories consumed/burned).
Q. Finally, what about environmental impact of meat?
A. While the debunked video gave some numbers, I look at this:
The biggest opportunities to move to lower greenhouse emission is transportation (thank you Tesla) and electricity generation ("Five states — Idaho, Vermont, Washington, South Dakota, and Oregon — and Washington, D.C., generate 70 percent or more of their power output from renewable sources."). In spite of the present POTUS, there is a lot happening on these fronts around the world. Even individually, putting on solar panels and driving an electric car (and not flying at all!!) is far more impactful than moving to vegetarian diets. (side note: flying is a great example of cost/benefit analysis. An individual's carbon footprint if they fly even once is larger than most anything else they do and yet we fly as net net it makes the world a better place by connecting people for both personal and professional reasons. We don't question the need for flying, do we?).
OK, that's enough!! Clearly I have been ruminating / acting on this topic for sometime.
Thanks for building a product that allows me to put it out there. Hopefully some people will thoughtfully challenge me and force to me improve/change my arguments.